Toner replenisher

ABSTRACT

A method and apparatus for supplying make-up toner particles to a toner mix in an electrostatic image printing machine. Pure toner is supplied to a hopper and the hopper has a gravity dispensing opening with a rotary brush serving as a door. The brush picks up toner particles in the mat thereof and a doctor blade flicks the bristle mat as the brush turns, to cause a flying cloud of toner particles which settle downwardly into a subjacent mixing chamber.

[4 1 Aug. 12, 1975 United States Patent [191 Andrako 7 77 3 33 6866 W WW3 l ll 11 011.

[54] TONER REPLENISHER 3,374,768 3/1968 Lawes et 3,396,872 8/1968Wheeler............ [75} Inventor: Thomas E. Andrako, Maple Helghts,3,669,072 6/1972 Reynolds et a1. OhlO 3,827,394 8/1974 Takahashi 6t [73]Assignee: Addressograph-Multigraph Primary Examiner-Mervin SteinAssistant ExaminerDouglas Salser [22] Filed:

Attorney, Agent, or Firm-Ray S. Pyle [57] ABSTRACT r d Pvt mmm tpfl Pe uw emO k h a mk o mt .m m. who. Sew n :m h .mr. mum wm 1m dm n a d m OSChe l h m mn n AP.... 8 2 .m%4 D 7 UGQJM 36 0 W. wmmm u M m n 7 m" 3 H m6 H /.u 8 H 1" 1m Wmh c ur- "Ma 6 s 02 C d S M UhF 1.11 2 00 555 [[1 thehopper has a gravity dispensing opening with a rotary brush serving as adoor. The brush picks up toner References Clted particles in the matthereof and a doctor blade flicks UNITED STATES PATENTS the bristle matas the brush turns, to cause a flying 118/637 cloud of toner particleswhich settle downwardly into a subjacent mixing chamber.

118/7 X 2 Claims, 4 Drawing Figures 2,715,585 8/1955 Schwartz et al.2,910,964 11/1959 Stavrakis et a1. 3,320,879 5/1967 Edwards et al.3,367,307 2/1968 Lawes ct "Wit PATENTEB AUG 1 2 I975 SHEET n w w r 0 f"H W M a A 0 in J Fm/l.

TONER REPLENISHER BACKGROUND OF THE INVENTION The original method ofadding toner particles to a depleted toner mix was simply to open up thecompartment and pour a quantity of the pure particle matter into themixing chamber and then allow mixing to take place for a period of timeto bring about a homogeneous mix.

Such addition methods produced enough toner air pollution andcontamination of workers hands that it was objectionable. Accordingly,mechanical addition devices of many and varied types have been developedfor both dry and liquid addition. An example is illustrated andnumbered, although not described, in US. Pat. No. 3,697,050. In theprior art reference a sponge roller blocks the exit opening of a hopperand the surface of the sponge roller is able to drag enough of the tonermaterial along with its surface to a scraping blade that the toner canbe scraped off into a mixing chamber.

SUMMARY OF THE INVENTION The purpose to be accomplished by thisinvention is the uniform dispersion of a controlled amount of tonermaterial into a mixing chamber avoiding all lump or batch injection andproducing a flying cloud which causes an acceleration of incorporationuniformly into a depleted toner mix.

DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. 1 is a mechanicalschematic of an automatic xerographic reproducing machine utilizing thepresent invention.

FIG. 2 is a top view of the dispensing unit of this invention takenalong the line 2-2 of FIG. 1.

FIG. 3 is a fragmentary section of a doctor blade and brush interfacetaken substantially along the line 33 of FIG. 1.

FIG. 4 is a perspective illustration of a cartridge to supply tonermaterial to the system, and is shown in section in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The electrostatic copy art is sothoroughly known that no effort is made to illustrate a complete workingmachine. There are many issued patents and technical journals whichcompletely illustrate such systems if reference is needed. As in allelectrostatic systems of the type under consideration, a light image ofan original to be reproduced is projected onto the sensitized surface ofa drum 10, whether that drum has a metal photoconductive surface forlater transfer of an image, or is a drum support for a paper platehaving a photoconductive insulating surface. It is immaterial to thisinvention which type surface is used. An electrostatic latent image isformed on that surface. Thereafter, the latent image is developed withan oppositely charged developing material comprising carrier beads andsmaller toner particles triboelectrically adhering thereto to form apowder image, corresponding to the latent image on the drum surface. Thepowder image is then electrostatically fused either directly upon thesurface where created, or transferred to a carrier upon which it is tobe permanently affixed.

The electrostatically attractable developing material commonly used inmagnetic brush developing apparatus comprises a pigmented resinouspowder referred to here as toner and a carrier of larger beads removedin the trioelectric series from the toner so that a triboelectric chargeis generated between the toner powder and the granular carrier. Thecarrier is magnetizable and also provides mechanical control for theformation of the brush bristles by virtue of magnetic fields so that thetoner can be readily handled and brought into contact with the exposedsurface. The toner is then attracted to the electrostatic latent imagefrom the carrier bristles to produce a visible powder image on aninsulating surface.

A series of magnetic rollers form the magnetic mix into a brush-likeformation following the magnetic path of magnets placed within theroller 14, in a well known manner described in US. Pat. No. 3,697,050and shown in further developed form in co-pending application Ser. No.337,340, titled QUALITY CONTROL OF ELECTROSTATIC IMAGE DEVELOPER MIX.

In applicants co-pending application, it is stated that as the developermix is depleted, a fine dust of replacement toner without magneticmaterial is caused to cascade from a supply source and become mixed intothe entire system as the toner floats and falls down into the cascadingmaterial being dumped from mixer buckets shown in phantom outline inFIG. 1 of the drawings.

The purpose of this invention is to supply the toner particles as a finedust cloud into an area 16, which may be termed a mixing chamber. A mixof non-consumable carrier members, such as glass particles or magneticiron particles, and consumable toner particles are mixed in chamber 16.After the toner mix is carried by the magnetic brushes in theillustrated embodiment, or otherwise depleted of its toner particlesupply, the spent mix is deposited back into the mixing chamber andcaused to be mixed with the supply of toner particles in the chamber inorder to carry the toner particles from the chamber back to the areawhere it is needed. Eventually the toner particles are carried out ofthe chamber to the extent that they must be re-supplied. This point intime is possible to be determined by observation of the output of themachine, but modern equipment provides monitoring devices which candetermine when the additional toner supply is needed.

This invention is directed to the improvement in toner particle supplyand it comprises generally a housing 20 which is seated on the top ofthe mixing chamber 16 over a supply entrance 18 in the chamber.

A brush of circular cross-section, which is preferably a cylindricalbrush, is mounted in the housing 20 adjacent to the entrance opening 18.Brush 22 has a bristle mat 24 at its exterior surface, and the brush isdriven in a rotary direction by means of an electric power train whichfeeds into the drive gear 26 shown best in FIG. 2. The balance of thepower train is conventional and need not be illustrated for the purposeof understanding this invention. However, it should be noted that suchpower train preferably is one which can be started and stopped at willand controlled in response to some chamber monitoring device whichindicates when sufficient toner supply is present or absent from mixingchamber 16.

A supply hopper 28 has an opening located with respect to gravity in aposition which will allow toner placed in the hopper to be expelled fromthe hopper through that opening. The opening is defined by short frontwalls 29 and sloping rear wall 30. Walls 29 and are formed by end walls31. The hopper is then located so that the brush 22 acts as a rotatingdoor for the opening between the terminal edge of walls 29 and 30 in thesupply hopper. In this respect the rotating brush is much like prior artsponge roller referred to above.

This invention differs markedly from the prior art, however, in that notonly is the brush one with a bristle mat 24, but the sloping rear wall30 of the hopper terminates in a doctor blade formation indicated by thereference character 32. Doctor blade 32 extends partially into the matof tin bristle mat 24 to cause the bristles to bend and then snap backafter the bristle passes the blade when the brush 22 is rotated.

The doctor blade 32 is shown as an integral part of the sloping rearwall 30, although obviously could be a separate structure if so desired.

In order to facilitate the formation of a uniform supply of cloud-liketoner material it has been found that the doctor blade action isenhanced by providing the doctor blade 32 with serrated teeth 33 asshown best in FIG. 3 of the drawings. Thus the bristle mat not only isbent back from the forward direction of roller movement but the bristlesare caused to separate laterally and snap back in a compound action.Such snapping action of a stiff bristle mat brush will cause the tonerparticles clinging to the brush bristle to fly free and form a cloudatmosphere on the exterior of the hopper and directly above the opening18. Hence, the cloud descends in a light mist into the mixing chamber 16and provides an even distribution of the product throughout the chamber.The mixing action is thus greatly facilitated.

Further enhancement of the cloud formation is provided by means ofavibrator 35 mounted to the sloping rear wall 30. As the back wallvibrates it will prevent any bridging of toner material in the hopperand thus cause an even flow of the material to the brush. How ever, itis very important that this vibration action enhances the flickingaction of the bristle mat and hence a better dispersing of the tonerparticles from the bristles of the roller.

A supply cassette 36 is designed to fit the top of the housing 20 overthe top entrance of the hopper 28. A drawer slide 38 is withdrawn toopen the bottom of the cassette after the cassette is installed.Therefore, all of the toner material is confined within closed walls toprevent air pollution and operator contamination.

In order to prevent the vibration of vibrator 35 from being transmittedto unwanted portions of the apparatus, the hopper 28 is mounted onsupport pins 40 by means of rubber grommets at each end wall 31, andproper adjustment of the hopper and the brush is obtained by means ofadjustment screws 42 which contact adjustment blocks 44.

What is claimed is:

1. In a toner system for electrostatic image development employing a mixof non-consumable carrier members and consumable toner particles, thesystem including a mixing chamber wherein spent mix is deposited andcaused to be resupplied with toner particles clinging thereto, saidchamber having a supply entrance opening above the mixing area;

the improvement in toner particle supply, comprising:

a housing seated on said chamber over said supply entrance opening;

a brush of circular cross-section mounted in said housing adjacent saidentrance opening, said brush having a bristle mat surface, and means forrotating said brush about its central axis;

a supply hopper located to expel toner from said hopper through saidopening by gravity, said hopper mounted adjacent said brush with saidbrush as the sole closure blocking the opening;

the hopper opening is rectangular, defined by a vertical front hopperwall and a sloping rear hopper wall terminating at a locationsubstantially directly below said front wall, and end walls;

a doctor blade formed by a serrated edge formation of said rear walltermination on the side of said opening from which the mat of said brushexits, said blade extending partially into said mat to cause thebristles to bend and then snap back after passing the blades; and

a vibrator means for vibrating said rear wall to shake toner down tosaid brush and to actuate the particle dispensing action of said brush;

whereby, the bristles pick up toner particles from a hopper supply, andflick the particles free in a descending cloud to said mixing chamber.

2. In a toner system for electrostatic image development employing a mixof non-consumable carrier members and consumable toner particles, thesystem including a mixing chamber wherein spent mix is deposited andcaused to be resupplied with toner particles clinging thereto, saidchamber having a supply entrance opening above the mixing area;

the improvement in toner particle supply, comprisa housing seated onsaid chamber over said supply entrance opening;

a brush of circular cross-section mounted in said housing adjacent saidentrance opening, said brush having a bristle mat surface, and means forrotating said brush about its central axis;

a supply hopper having an opening located to expel toner from saidhopper through said opening by gravity, said hopper mounted adjacentsaid brush with said brush as the sole closure blocking the opening;

a doctor blade at said hopper opening on the side of said opening fromwhich the mat of said brush exits, said blade extending partially intosaid mat to cause the bristles to bend and then snap back after passingthe blade; and

a vibrator mounted to act upon said doctor blade to accelerate theparticle dispensing action;

whereby, the bristles pick up toner particles from a hopper supply, andflick the particles free in a descending cloud to said mixing chamber.

1. In a toner system for electrostatic image development employing a mixof non-consumable carrier members and consumable toner particles, thesystem including a mixing chamber wherein spent mix is deposited andcaused to be resupplied with toner particles clinging thereto, saidchamber having a supply entrance opening above the mixing area; theimprovement in toner particle supply, comprising: a housing seated onsaid chamber over said supply entrance opening; a brush of circularcross-section mounted in said housing adjacent said entrance opening,said brush having a bristle mat surface, and means for rotating saidbrush about its central axis; a supply hopper located to expel tonerfrom said hopper through said opening by gravity, said hopper mountedadjacent said brush with said brush as the sole closure blocking theopening; the hopper opening is rectangular, defined by a vertical fronthopper wall and a sloping rear hopper wall terminating at a locationsubstantially directly below said front wall, and end walls; a doctorblade formed by a serrated edge formation of said rear wall terminationon the side of said opening from which the mat of said brush exits, saidblade extending partially into said mat to cause the bristles to bendand then snap back after passing the blades; and a vibrator means forvibrating said rear wall to shake toner down to said brush and toactuate thE particle dispensing action of said brush; whereby, thebristles pick up toner particles from a hopper supply, and flick theparticles free in a descending cloud to said mixing chamber.
 2. In atoner system for electrostatic image development employing a mix ofnon-consumable carrier members and consumable toner particles, thesystem including a mixing chamber wherein spent mix is deposited andcaused to be resupplied with toner particles clinging thereto, saidchamber having a supply entrance opening above the mixing area; theimprovement in toner particle supply, comprising: a housing seated onsaid chamber over said supply entrance opening; a brush of circularcross-section mounted in said housing adjacent said entrance opening,said brush having a bristle mat surface, and means for rotating saidbrush about its central axis; a supply hopper having an opening locatedto expel toner from said hopper through said opening by gravity, saidhopper mounted adjacent said brush with said brush as the sole closureblocking the opening; a doctor blade at said hopper opening on the sideof said opening from which the mat of said brush exits, said bladeextending partially into said mat to cause the bristles to bend and thensnap back after passing the blade; and a vibrator mounted to act uponsaid doctor blade to accelerate the particle dispensing action; whereby,the bristles pick up toner particles from a hopper supply, and flick theparticles free in a descending cloud to said mixing chamber.